1. Field of the Invention
The present invention relates to an information processing device for processing traffic information on past traffic conditions, a system thereof, a method thereof, a program thereof, and a recording medium storing such a program.
2. Description of Related Art
Vehicle navigation devices adapted to acquire traffic information on vehicle accidents, traffic jams and so on from a VICS (vehicle information communication system) and superimpose the acquired traffic information (on vehicle accidents, traffic jams and so on) on map information being displayed on a display unit of the vehicle navigation device for the purpose of notifying a user of the information are known. Meanwhile, when a traffic jam occurs, drivers who want to avoid the traffic jam may make a detour to consequently give rise to a secondary traffic jam. Since the VICS provides only the current traffic condition, drivers who make a detour, seeing the current traffic condition provided by the system, can be engulfed in a secondary traffic jam. Thus, there is a demand for improved vehicle navigation device that allow users to avoid traffic jams and take the best route to get to the destination.
On the other hand, vehicle navigation devices adapted to predict the traffic condition for now and in the future by using statistic data on traffic jams obtained by statistically processing information on past traffic jams and notify users of the predicted traffic condition for now and in the future are known (see prior art 1: Japanese Patent Laid-Open Publication No. 9-113290, p. 3, right column-p. 7, left column). A vehicle navigation device described in the above-cited prior art 1 is so designed that, upon recognizing an input by the user of a day of the week, a time zone and so on, it retrieves statistic traffic jam information data including statistic traffic jam information for the day of the week and the time zone input by the user and notifies the user of the retrieved statistic traffic jam information by superimposing it on the map information being displayed on the device in a display format that may vary depending on the traffic jam condition. With this arrangement, the user can predict the traffic jams that can take place now and those that can take place in the future according to the traffic jam information for the day of the week and the time zones of a day.
Further, when the navigation device as disclosed in the above-cited prior art 1 recognizes that an event such as a festival takes place on the day and in the time zone input by the user it retrieves statistic restrictions information data including statistic traffic jam information for the day and the time zone of the event that are input by the user. Then, the device notifies the user of the retrieved statistic restrictions information and notifies the user of the retrieved statistic restrictions information by superimposing it on the map information being displayed on the device in a display format that may vary depending on the traffic jam condition. With this arrangement, the user can predict the traffic jams that can take place now and those that can take place in the future due to the event on the day of the event.
However, the technique disclosed in the above-cited patent document is accompanied by problems. For example, if the day when the event is held can vary from year to year, for instance while it was held on August 1st last year but will be held on August 3rd this year, the statistic restrictions information data that corresponds to the day and the event may need to be updated every year and, since such statistic restrictions information data generally include statistic traffic jam information having a large volume of information, the operation of updating such statistic restrictions information data having a large volume of information every year imposes a large operational load.